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Delta Island is a small above sea level biome in Subnautica: Below Zero, and the location of Delta Station and the Communications Tower.

The biome is surrounded by the Thermal Spires, Purple Vents and Tree Spires. Koppa Mining Site is located underneath the island, with entrances found near its coast.


Delta Island is a small rocky landmass with a dark sediment base and covered in snow. The island is highly weathered, with many fragmented and degraded rock layers present on the surface. The island is populated by several large flora species and Pengwings.

Several hot springs are found here and often contain Crystalline Sulfur. The player will be able to use these along with Thermal Lilies in order to keep their body temperature high.

Five Diamonds can be obtained in a cave through the use of a Spy Pengling to travel through a narrow opening in that cave, which also contains a large amount of Calaverite Outcrops. There's a staircase leading down to this cave close to the Delta Station's sign.

A Material Analysis Station can be found alongside an Ion Cube on the southern region of the island, reached by either walking east along the shore from the dock or swimming into the shore from the Thermal Spires.


Robin Ayou has to visit Delta Island numerous times during her adventures. It is where she first encounters Marguerit Maida, and she is later given the task of sabotaging the Communications Tower to block Alterra satellite surveillance.



  • Delta Island was originally named Rocket Island.
    • This is due to the fact that the Exchanger Rocket was found on the Delta Island in previous versions of the story.